The following represent typical patents in this art.
U.S. Pat. No. 718,589, to C. A. Tredwell for Retaining Device for Fish Line Reels, discloses a finger-hold for a casting rod, comprising a thin curved band whose intended purpose is to prevent the fishing line reel from working loose during use by maintaining constant finger pressure on the finger hold.
U.S. Pat. No. 834,571, to T. B. Galbraith for Finger Hook for Fishing Rods, discloses a removable fingerhook that may be used with a casting rod. This product shows a locator for the index finger that may be useful in preventing the rod from slipping from the grasp of the angler when casting.
U.S. Pat. No. 2,482,192, to R. A. MacDonald for Hand Saddle (to be used with casting rods), comprises a rigid shield-like portion curved to conform to a fishing rod and curved to provide a seat to conform to the side of the angler's index finger; it also includes a rigid side rest for the tip of the index finger and means for clamping this saddle to the rod.